I'm no software expert, but I think there are a few upgrades that would keep some of this stuff off.
Also, screening new members and approving their account when they register will help. Most of the time you can tell some of these people apart, especially when they fill in their profile or signature.
If you need more moderators, I'd add the members that are on the board frequently that you know post often or sign in the most. More moderators won't fix this, but will help keep the crap away. When the spammers post, delete the post, then ban them and their IP address.
